Fast Facts

Barra is a system comprising an expendable sonobuoy and an aircraft system. The sonobuoy listens for sounds emitted by a submarine and transmits them to the aircraft where they are processed and displayed.

It was invented by DSTO. Australia developed the sonobuoy and the UK the airborne processor.

Barra has been in service for over 30 years and is still used by the Royal Australian Air Force and the (UK) Royal Air Force.

More than 30,000 sonobuoys have been manufactured.

The project has contributed the national economy and to employment: the total value of contracts is estimated at $500M (allowing for inflation to 2010).

Research and development is continuing into other variants of directional sonobuoy systems, made active using underwater sound sources.